Light valve and display device

ABSTRACT

The present invention provides a light valve device, comprising a driving substrate having a shading zone and a photic zone, a shading unit, and the shading unit comprises a first shading plate, two driving units, and second shading plates respectively connected to the two driving units, and the driving unit and the first shading plate are fixed in the shading zone adjacent to the driving substrate, and the first shading plate is between the two driving units, and the driving unit can drive the two second shading plates close to the first shading plate to make the second shading plate face the photic zone of the driving substrate for preventing light entering the driving substrate. By locating the light valve device under the sub pixel, the dynamic contrast can be raised to promote the display effect.

CROSS REFERENCE

This application claims the priority of Chinese Patent Application No.201510326084.2, entitled “Light valve and display device”, filed on Jun.12, 2015, the disclosure of which is incorporated herein by reference inits entirety.

FIELD OF THE INVENTION

The present invention relates to a microelectromechanical system displaytechnology field, and more particularly relates to a light valve and adisplay device.

BACKGROUND OF THE INVENTION

At present, the main structure of the LCD panel on the market is shownin FIG. 1, and comprises a backlight source 1, a light guide plate 2, abrightness enhancement film 3, a lower polarizer 4, a TFT substrate 5, aliquid crystal layer 6, a color filter 7, an upper polarizer 8 and areflective sheet 9. The voltage applied to the liquid crystal layer iscontrolled for manipulating the rotations of the liquid crystalmolecules. Thus, a small angle change occurs to the polarizationdirection of the linearly polarized light generated with the lightemitted by the backlight passing through the lower polarizer. The lightpasses through the color filter and forms color of various colors.Because the polarization direction of the light and the transmissionaxis of the upper polarizer have different included angles, theintensity of the emitting light can be controlled to form the displayimage that we want.

However, in prior arts, the liquid crystal itself in the liquid crystaldisplay does not illuminate and has to rely on the backlight to providethe light source. With some reasons that the orientations of the liquidcrystal molecules cannot perfectly satisfy the design requirements, asshowing the black image, the pixels cannot be completely off, and somelight still exiting out from the panel, which results in that thecontrast cannot be reduced and the requirement of high quality from theconsumers cannot be satisfied.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a light valve usingMEMS to raise the dynamic contrast of the display device for enhancingdisplay effect.

Another objective of the present invention is to provide a displaydevice using the aforesaid light valve.

For realizing the aforesaid objective, the technical solution providedby the embodiments of the present invention is:

the light valve device of the present invention comprises a drivingsubstrate having a shading zone and a photic zone, a shading unit, andthe shading unit comprises a first shading plate, two driving units, andsecond shading plates respectively connected to the two driving units,and the driving unit and the first shading plate are fixed in theshading zone adjacent to the driving substrate, and the first shadingplate is between the two driving units, and the driving unit can drivethe two second shading plates close to the first shading plate to makethe second shading plate face the photic zone of the driving substratefor preventing light entering the driving substrate.

The light valve device further comprises a swing arm, and the secondshading plate and the driving unit are connected with the swing arm, andthe driving unit drives the swing arm to rotate the second shading platein a facing region of the shading zone and a facing region of the photiczone to accomplish state switch of the light valve.

A high scattering coated layer is coated on the shading plate, thedriving unit and surfaces of the swing arm to raise a light useefficiency.

The present invention further provides a display panel comprising commonelectrode lines and a plurality of sub pixels, wherein each sub pixelcomprises a light valve device, and the light valve device comprises adriving substrate having a shading zone and a photic zone, a shadingunit, and the shading unit comprises a first shading plate, two drivingunits, and second shading plates respectively connected to the twodriving units, and the driving unit and the first shading plate arefixed in the shading zone adjacent to the driving substrate, and thefirst shading plate is between the two driving units, and the drivingunit can drive the two second shading plates close to the first shadingplate to make the second shading plate face the photic zone of thedriving substrate for preventing light entering the driving substrate.The sub pixel further comprises a thin film transistor, a drain of thethin film transistor is coupled to an input end of the driving unit andan output end of the driving unit is coupled to the common electrodeline.

The light valve device further comprises a swing arm, and the secondshading plate and the driving unit are connected with the swing arm, andthe driving unit drives the swing arm to rotate the second shading platein a facing region of the shading zone and a facing region of the photiczone to accomplish state switch of the light valve.

A high scattering coated layer is coated on the shading plate, thedriving unit and surfaces of the swing arm to raise a light useefficiency.

The display panel further comprises a color filter, a brightnessenhancement film and a lower polarizer, and the lower polarizer islocated between the color filter and the brightness enhancement film,and the light valve device is located between the brightness enhancementfilm and the lower polarizer.

The color filter comprises black zones distributed in matrix, and theshading zone of the driving substrate is oppositely located to the blackzone.

The display panel further comprises a color filter, a brightnessenhancement film and a light guide plate, and the brightness enhancementfilm is located between the color filter and the light guide plate, andthe light valve device is located between the brightness enhancementfilm and the light guide plate.

The color filter comprises black zones distributed in matrix, and theshading zone of the driving substrate is oppositely located to the blackzone.

The display panel further comprises a color filter, a light guide plateand a reflective sheet, and the light guide plate is located between thecolor filter and the reflective sheet, and the light valve device islocated between the reflective sheet and the light guide plate.

The color filter comprises black zones distributed in matrix, and theshading zone of the driving substrate is oppositely located to the blackzone.

The embodiments of the present invention have advantages or benefits:

By the method of locating MEMS light valve in each sub pixel, thepresent invention realizes the control to the backlight in each subpixel for achieving the objective of promoting the dynamic contrast ofeach sub pixel and thus, promoting the display effect of the displaydevice.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the presentinvention or prior art, the following figures will be described in theembodiments are briefly introduced. It is obvious that the drawings aremerely some embodiments of the present invention, those of ordinaryskill in this field can obtain other figures according to these figureswithout paying the premise.

FIG. 1 is a structural diagram of a LED panel structure according toprior art;

FIG. 2 is an enlarged diagram of a light valve in close state accordingto the present invention;

FIG. 3 is an enlarged diagram of the light valve according to theembodiment of the present invention;

FIG. 4 is a diagram of a display device of the second kind having thelight valve shown in FIG. 2.

FIG. 5 is a diagram of a color filter black matrix according to thepresent invention;

FIG. 6 is a diagram of a display device of the second kind having thelight valve shown in FIG. 2;

FIG. 7 is a diagram of a display device of the third kind having thelight valve shown in FIG. 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Embodiments of the present invention are described in detail with thetechnical matters, structural features, achieved objects, and effectswith reference to the accompanying drawings as follows. It is clear thatthe described embodiments are part of embodiments of the presentinvention, but not all embodiments. Based on the embodiments of thepresent invention, all other embodiments to those of ordinary skill inthe premise of no creative efforts obtained, should be considered withinthe scope of protection of the present invention.

Please refer to FIG. 2. The light valve device 200 comprises a drivingsubstrate 12. A partial zone (photic zone 122) on the driving substrate12 is photic, and other zone (shading zone 121, covered with a blackmatrix) is opaque. The shading zone 121 and the photic zone 122 arelocated in space and alternately distributed. The shading zone 121 isemployed to stop the light pass through. The light at the photic zone122 can passes through the driving substrate 12. The light valve device200 further comprises a shading unit (not numbered). The shading unitcomprises a driving unit 11, a first shading plate 15, and two secondshading plates 10, and the driving unit 11 and the first shading plate15 are fixed in the shading zone 121 of the driving substrate 12, andthe second shading plate 10 is connected to the driving unit 11, and thefirst shading plate 15 is located between the two second shading plate10.

Each light valve 200 corresponds to one sub pixel. As the sub pixelcorresponded with two adjacent photic zone 122 needs the backlight topenetrate, the second shading plate is located in the shading zone 121.i.e. the light valve device 200 is in on state. The backlight candirectly enter the driving substrate 12 through the two photic zone 122,and the pixel does not show black; please refer to FIG. 3, as the subpixel corresponded with the light valve 200 needs to show black, withbeing driven by the driving unit 11, the two second shading plates 10get close to the first shading plate 15. Then, the second shading plate10 right faces the photic zone 122 for preventing the backlight enteringthe driving substrate 12 through the phtoic zone 122, i.e. the lightvalve device 200 is in off state. The sub pixel corresponded with thelight valve 200 is completely off to form high contrast with theperiphery to promote the display effect.

Furthermore, the second shading plate 10 and the driving unit 11 can beconnected with a swing arm 14.

The swing arm 14 can use heat induced deformation element (such as shapememory alloy), electricity induced deformation element to be the maincomponent. The swing arm drives the second shading plate 10 to rotate.Furthermore, for reducing the light energy loss and promoting the lightuse efficiency, a high scattering coated layer is coated on the firstshading plate 15, the two second shading plates 10 and the swing arm 14to raise a light use efficiency to reflect the light emitting to thecoated layer back to the backlight path to reduce the light energy loss.

Please refer to FIG. 4. This embodiment further provides a displaydevice 100, comprising a plurality of sub pixels. The sub pixels can bevarious colors. Each sub pixel comprises a light valve, and at least aportion of the light valves is the aforesaid light valve device 200. Thedisplay device 100 comprises an upper polarizer 8, a color filter 7, aliquid crystal layer 6, a TFT substrate 5, a lower polarizer 4, a lightvalve device 200, a brightness enhancement film 3, a light guide plate 2and a reflective sheet 9 from top to bottom in sequence. The backlightsource 1 is located at the lateral side of the light guide plate 2. Thelight valve device 200 is located between the brightness enhancementfilm 3 and the lower polarizer 4. The color filter 1 is employed toachieve the colorization of the image after the light emitted from thebacklight module passes through the color filter 1. The color filter 1comprises a RGB color film layer (i.e. red color film, green color filmand blue color film) (not shown) and a black zone distributed in matrix(black matrix) (not numbered). Please refer to FIG. 5. The black matrixfurther comprises a plurality of black matrix elements 52. The pluralityof black matrix elements 52 are located on the color filter 1 spacedwith certain distances. The shading zone 121 of the driving substrate 12faces the black matrix, and the photic zone 122 of the driving substrate12 faces the spaces 53 (i.e. the photic zone on the color filter 1)among the black matrix elements. Obviously, the amount, dimensions,shapes and positions of the shading zones 121 and the photic zones 122of the driving substrate 12 match with the black matrix elements 52 andthe spaces 53 of the color filter 1.

The display device 100 further comprises common electrode lines (nowshown), a plurality of gate lines (not shown) and data lines (not shown)which intersect with one another. Each intersecting location of the gatelines and data lines is a pixel. The sub pixel further comprises a thinfilm transistor, and a gate of the thin film transistor is coupled tothe gate line, and a source is coupled to the data line, and the inputend of the driving unit 11 is coupled to the drain of the thin filmtransistor, and the output end is coupled to the common electrode line.By providing the driving signal to the driving unit 11 through the thinfilm transistor, the display contents of the respective sub pixels canbe independently controlled.

Correspondingly, the shading zone 121 of the driving substrate 12 can beany opaque structure. However, with consideration in aspects of weight,cost technology maturity level, the black matrix is preferred. That isto say, the black matrix material in the color filter 1 can be employedto be the shading zone 121. The black matrix material can be metal ofresin of which the opacity is stronger.

Please refer to FIG. 6. In the second embodiment of the display device100, the light valve device 200 is located between the brightnessenhancement film 3 and the light guide plate 2. The working principle issimilar with the display device 100 in the first embodiment. Therepeated description is omitted here.

Please refer to FIG. 7. In the third embodiment of the of the displaydevice 100, the light valve device 200 is located between the reflectivesheet 9 and the light guide plate 2. When the sub pixel needs to showblack, with being driven by the driving unit 11, the two second shadingplates 10 get close to the first shading plate 15 to make the secondshading plate 10 face the photic zone 122 for preventing the backlightentering the reflective sheet 9 through the phtoic zone 122, and thus,the sub pixel here shows black.

Above are embodiments of the present invention, which does not limit thescope of the present invention. Any modifications, equivalentreplacements or improvements within the spirit and principles of theembodiment described above should be covered by the protected scope ofthe invention.

What is claimed is:
 1. A light valve device, comprising a drivingsubstrate having a shading zone and a photic zone, wherein the lightvalve device further comprises a shading unit, and the shading unitcomprises a first shading plate, two driving units, and second shadingplates respectively connected to the two driving units, and the drivingunit and the first shading plate are fixed in the shading zone adjacentto the driving substrate, and the first shading plate is between the twodriving units, and the driving unit can drive the two second shadingplates close to the first shading plate to make the second shading plateface the photic zone of the driving substrate for preventing lightentering the driving substrate.
 2. The light valve device according toclaim 1, wherein the light valve device further comprises a swing arm,and the second shading plate and the driving unit are connected with theswing arm, and the driving unit drives the swing arm to rotate thesecond shading plate in a facing region of the shading zone and a facingregion of the photic zone to accomplish state switch of the light valve.3. The light valve device according to claim 2, wherein a highscattering coated layer is coated on the shading plate, the driving unitand surfaces of the swing arm to raise a light use efficiency.
 4. Adisplay panel comprising common electrode lines and a plurality of subpixels, wherein each sub pixel comprises a light valve device, and thelight valve device comprises a driving substrate having a shading zoneand a photic zone, a shading unit, and the shading unit comprises afirst shading plate, two driving units, and second shading platesrespectively connected to the two driving units, and the driving unitand the first shading plate are fixed in the shading zone adjacent tothe driving substrate, and the first shading plate is between the twodriving units, and the driving unit can drive the two second shadingplates close to the first shading plate to make the second shading plateface the photic zone of the driving substrate for preventing lightentering the driving substrate.
 5. The display panel according to claim4, wherein the light valve device further comprises a swing arm, and thesecond shading plate and the driving unit are connected with the swingarm, and the driving unit drives the swing arm to rotate the secondshading plate in a facing region of the shading zone and a facing regionof the photic zone to accomplish state switch of the light valve.
 6. Thedisplay panel according to claim 5, wherein a high scattering coatedlayer is coated on the shading plate, the driving unit and surfaces ofthe swing arm to raise a light use efficiency.
 7. The display panelaccording to claim 4, wherein the display panel further comprises acolor filter, a brightness enhancement film and a lower polarizer, andthe lower polarizer is located between the color filter and thebrightness enhancement film, and the light valve device is locatedbetween the brightness enhancement film and the lower polarizer.
 8. Thedisplay panel according to claim 7, wherein the color filter comprisesblack zones distributed in matrix, and the shading zone of the drivingsubstrate is oppositely located to the black zone.
 9. The display panelaccording to claim 4, wherein the display panel further comprises acolor filter, a brightness enhancement film and a light guide plate, andthe brightness enhancement film is located between the color filter andthe light guide plate, and the light valve device is located between thebrightness enhancement film and the light guide plate.
 10. The displaypanel according to claim 9, wherein the color filter comprises blackzones distributed in matrix, and the shading zone of the drivingsubstrate is oppositely located to the black zone.
 11. The display panelaccording to claim 4, wherein the display panel further comprises acolor filter, a light guide plate and a reflective sheet, and the lightguide plate is located between the color filter and the reflectivesheet, and the light valve device is located between the reflectivesheet and the light guide plate.
 12. The display panel according toclaim 11, wherein the color filter comprises black zones distributed inmatrix, and the shading zone of the driving substrate is oppositelylocated to the black zone.